I think HT should just get the elephant out of the room. Most of us (I'm speaking realistically, of course) believe that Batman is the only figure that we're guaranteed, with a Joker if we're lucky. Think of it this way:
TDKR:
Batman, Bane, Catwoman, 1/4 Batman, 1/4 Bane (potentially), 1/4 Catwoman (potentially).
Batman Returns: Batman, Penguin, Catwoman, 1/4 Batman, 1/4 Penguin (potentially), 1/4 Catwoman (potentially).
The general consensus is that we're going to see the least amount of merchandise from the Arkham City, so why not get it out of the way before they start on the other, potentially more expansive Batman licenses. That way, if they decide to revisit the line later, after the movie stuff has died down, we'll be happy, but if not, then we have no expectations that we'll be seeing more figures after Batman and Joker, if we see that after Joker they've started on the TDKR, Returns, etc. stuff. If that makes any sense.